In a communications system, such as a telephone system, provisions are made for charging the customers according to their individual use of the system. Billing data such as the identity of the customer originating the call, the identity of the called customer, and the time of day that the call was made is generally recorded along with the time the called customer answers and the time of disconnect. This information can then be used to calculate the charges for billing the customers for each call.
There are many prior art message billing schemes used in telephony, and while they are generally suitable for their intended purpose, they lack certain features we have incorporated in the present arrangement.
In one known prior art arrangement a plurality of marker circuits common to the customer lines is used for controlling the establishment of connections through the switching system. During the processing of a call, the marker assembles the calling and called customer identities in order to establish this connection. It is undesirable, however, to detain the marker to permit the billing data to be recorded on a permanent media, since while the marker is being detained, it cannot be used for processing other calls. The marker, therefore, seizes another common circuit called a sender and passes the billing data to the sender which awaits service by the automatic message accounting system.
Senders are generally used for outpulsing the called number to a distant office; however, in these prior art billing arrangements a sender must always be used, even though no outpulsing is required such as on an intraoffice call.
Other prior art schemes provide toll ticketing equipment which is associated with the individual trunks of the telephone system. In some cases, each trunk is equipped with registers to record the calling and called customer identities along with the duration of the call. In other systems the ticketing equipment is shared by a group of trunks and is only associated with a trunk for the duration of the call. At some convenient time during a period of light traffic, the billing data stored in the toll ticketing equipment can be extracted by a data processor which computes the charges for the individual calls.
While this latter arrangement does not require the use of a sender on all calls, the provision of a multiplicity of toll ticketing registers associated with the trunks may be inefficient. Economics can be realized by centralizing the message billing functions under the control of a high speed data processor.